Overhead doors are not new and are seen frequently in buildings such as homes, automotive shops, barns, aircraft and blimp hangars, commercial warehouses, portable military field structures, and the like. A wide variety of doors are currently used in industrial and other settings. For example, one type of movable door consists of a series of generally horizontal panels disposed one on top of the other with each panel hinged to the panel above. Stemmed rollers are disposed on opposed lateral edges adjacent a bottom and top location of each door panel. Such sectional doors are typically movable between a closed or blocking position and an open or stored position relative to a doorway. For this purpose, guide tracks having a generally “C” shaped cross-section are provided on either side of the doorway for receiving the rollers disposed on the adjacent edges of each of the panels. Each track has a substantially vertical portion disposed adjacent and parallel to the doorway opening, a substantially horizontal portion disposed above and behind the doorway generally perpendicular to the doorway opening, and a connecting curved portion. A track is positioned on either side of the doorway providing a continuous guide track for receiving the stemmed rollers of the adjacent panel sections. In this construction, the door is substantially horizontal when in the open or stored position. Another type of movable door is a vertically storable door which moves in a continuous generally vertical plane between the closed and open (stored) positions along substantially straight and vertical guide tracks disposed from floor level of the door opening to a location above the doorway opening. The lifting force needed to counterbalance the door is recognized to vary so that different types of lifting assist devices are used to provide a statically balanced overhead door i.e. a door that will maintain a position assigned to it by an operator (user). The position can be closed, open or any location in between.
One type of garage door operating mechanism is the so called torsion spring control system. The torsion spring control system uses a shaft around which are disposed control springs to provide the counterbalance for the door. This type of mechanism avoids the use of extension springs but the torsion spring is exposed and can provide a source of injury if repairs or adjustments are attempted by one not skilled in working with such devices.
Another type of counterbalancing mechanism comprises horizontally extendable springs disposed above and generally parallel to the horizontal portion of the guide tracks for counteracting the effect of gravity on the door as it moves between a closed and an open (stored) position or from an open to a closed position. Such counterbalance devices typically include a cable system with a pair of cables attached to the opposite edges of the door with springs connected to each of the cables. In the door open or stored position the spring is not extended, eg. Relaxed or compressed. When the door moves from the stored position, the spring extends or is streched providing a force which counteracts the weight of the door. In this way, the spring controls the descent of the door as it moves toward the closed position. Conversely, when the door is raised from the (doorway-blocking) closed position, the contracting spring provides a lifting force which makes the door easier to raise. Unfortunately, such mechanisms are complicated to assemble, they lack aesthetic appeal and expose the user to potential injury if the spring or cable breaks.
It would therefore, be desirable to house counterbalancing mechanisms within the door itself, thereby providing a more user friendly installation and an aesthetically pleasing door assembly with internal components that are unexposed reducing the potential of injury to a user.
U.S. Pat. No. 6,505,381, teaches using pulleys and a cable in conjunction with a hinge system for deploying panels or other structures from a satellite or spacecraft. The hinge system is placed within a telescoping housing in the deployed position.
U.S. Pat. No. 5,560,658, teaches an overhead bi-fold door with the cable and pulley system within the frame of the door to unlatch the door.
U.S. Pat. No. 6,042,158, discloses a cable actuated locking system inside the body of an overhead door.
U.S. Pat. Nos. 3,774,341 and 4,248,016, teach cable and spring operating systems for overhead doors that are positioned in the frame around the door.
U.S. Pat. No. 1,530,762, teaches a dual race cable drum having an inner race that spools a cable connected to a tensioning member and a larger outer race with separate cables connected to the door bottom.
U.S. Pat. No. 6,134,835 teaches a worm-gear drive winding mechanism to effect the winding of torsion springs on an up-ward acting door. It is supported by brackets attached to the wall above the door, with cables that depend from the counterbalance system and connect to the lower side edges of the door.
U.S. Pat. Nos. 2,291,583; 5,404,927 5,495,640; 6,112,464; 6,263,948 and 6,588,482 teach cable attachment brackets on the bottom edge of an upward acting door to receive the counterbalance cable which lifts the door.
U.S. Pat. No. 6,561,256, teaches opposed independent extension springs and lift cables of an overhead door to synchronize by means of an interconnected drive tube mounted above the door.
U.S. Pat. No. 3,747,274 teaches a cable and spring actuated locking system mounted on a vertically disposed door.
U.S. Pat. No. 5,103,890 teaches an overhead door system to be counterweighted with cables that depend from differential cable drums on a shaft mounted above the door with separate cable drums and cables that depend for attachment on the bottom edge of the door.
U.S. Pat. No. 6,289,966 teaches a door with a counterweight unit mounted on the uppermost door leaf.
U.S. Pat. No. 6,568,454 teaches the counterbalance system mounted above an overhead door to be rotated by an operator motor assembly.
U.S. Pat. No. 1,724,995 teaches an overhead door to be counterbalanced by the resilient action of a torsion spring upon a shaft with flanged pulleys spooling steel tape attached to the bottom of the door.
U.S. Pat. No. 1,059,981 teaches a bi-fold warehouse door to lift by chains secured to the bottom of the door with separated lateral bearing studs.
U.S. Pat. Nos. 1,724,995 and 2,882,044, teach operating the torsion shaft of a counterbalance assembly above a door to be rotated by an operator motor.
U.S. Pat. No. 1,661,719 teaches an endless chain driven by a motor carry to a trolley or carriage which is movable to the front and rear of a T-irons runway above an overhead door with the carriage linked to the door, whereby the door may be pulled or pushed effecting the opening and closing of the door.
U.S. Pat. No. 2,253,170 teaches an electric motor to turn a drive screw which carries a nut affixed to a carriage that travels forward and backward on a channel above a garage door and opens and closes the door.
The above two patents do not teach a linear drive motor mechanism to be significantly shorter in length as the distance the extension spring extends or retracts is far less in proportion to the full length of travel of the door. The length of a typical chain or screw drive opener mounted above a door is 10′. The length of the extension of the spring on the same door would be 3.3′ or approximately ⅓ the distance of travel. Further mechanical control of speed and force will be recognized as well.
U.S. Pat. Nos. 2,015,402; 2,568,808 and U.S. Pat. No. 5,036,899 teach a lateral shaft mounted on the top section of an overhead door to rotate with tension applied to the shaft by torsion spring means and pinions outboard of the lateral edges of the door which engage racks along the door tracks effecting the counterbalance of the weight of the door with rotation of the lateral shaft by a motor carried on the door.
U.S. Pat. No. 2,676,294 teaches opposed independent extension springs and lift chains of an overhead door to synchronized by combining sprockets on a shaft, above the door, to unify the lift chains and further permit rotation of the shaft directly by a motor assembly.
U.S. Pat. No. 4,468,904 teaches functionally connected torsion springs to counterbalance a telescoping tower.
U.S. Pat. No. 5,577,544 teaches a cable reeling device to affect the extension of a spring parallel with the horizontal track of an overhead door. An extension spring containment tube which surrounds the entire periphery of an extension spring over its operational length is also disclosed.
U.S. Pat. No. 5,632,063 teaches a worm drive ring shaped gear winding mechanism to affect the winding of torsion springs above an overhead door.
U.S. Pat. No. 1,508,886 teaches providing garage door units which may be assembled, in part, at a factory and shipped to a garage to be easily and quickly installed, that affords a safe and durable closure for the garage.
None of the prior art teach or suggest a garage door having a novel or conventional counterbalance mechanism enclosed within a panel of the door nor cables and pulley systems within a panel of the door with the cable exiting the door to a fixed location outside of the door.